Heat transfer

ABSTRACT

An image-receiving sheet comprising a base sheet and a receiving layer, provided on one surface of said base sheet, for receiving a dye or a pigment migrating from a heat transfer sheet, said base sheet comprising one or two or more layers, at least one layer of said base sheet having a porous structure or a foamed structure.

This application is a Rule 60 continuation of application Ser. No.08/005,806 filed Jan. 19, 1993, now U.S. Pat. No. 5,292,710, which inturn is a Rule 60 continuation of Ser. No. 07/798,354 filed Nov. 21,1991, now U.S. Pat. No. 5,210,068, which in turn in a Rule 62continuation application of Ser. No. 07/612,994, filed Nov. 15, 1990,now abandoned, which is a Rule 60 continuation application of Ser. No.07/168,908, filed Mar. 16, 1988, now U.S. Pat. No. 5,001,106.

BACKGROUND OF THE INVENTION

This invention relates to an image-receiving sheet which is used incombination with a heat transfer sheet, for performing recordingcorresponding to information by heat transferring the dye or pigment inthe heat transfer sheet.

The heat transfer recording system has been widely utilized as therecording system in a printer such as that in a computer, wordprocessor, and other devices. In recent years, attempts have been madeto use a heat-transfer sheet having a heat transfer layer containing asublimatable dye provided on the surface of a substrate such aspolyethyleneterephthalate in combination with an image-receiving sheetand perform overlayed recording of cyan, magenta, yellow, etc. therebyto accomplish recording of images of natural color photographic tones onsaid image-receiving sheet. This technique is being utilized in the caseof, for example, recording an image directly on a CRT display.

As such image-receiving sheets, those with a construction having areceiving layer provided on the surface of a resin with high heatresistance such as polyethyleneterephthalate, non-foamed film ofpolypropylene type resin, or a synthetic paper using a polyolefin typeresin or a polystyrene type resin as the base material have been knownin the art.

However, an image-receiving sheet using polyethyleneterephthalate, etc.,as the substrate may incur a lowering in its transferred image densitydue to high rigidity and low thermal insulating property of thesubstrate, and yet sometimes smooth sheet delivery may not be obtained.Consequently, there have been the drawbacks such as printing drift orcolor drift occurring when overlayed printing is repeated several timesas in color printing, whereby transferred images of high sharpness couldnot be obtained.

Also, while printing according to the heat transfer system has been doneby means of a heating printing means such as a thermal head, since theheat during transfer is applied only from one direction of the sheet inthe image-receiving sheet of the prior art, the substrate of theimage-receiving sheet curls so that the receiving layer side is on theconcave inner side, thus resulting in the drawback of poor transfer.

Further, after a desired image has been once transfer recorded on areceiving layer by heating the heat transfer sheet as described above bymeans of a thermal head, the image may be transferred onto atransferable article such as telephone card in some cases. When used astransferred on a transferable article, a transparent image-receivinglayer is provided on a transparent substrate, and after forming, forexample, a reverse image on the image-receiving layer, heat transfer iscarried out directly on an article, or through an adhesive sheet in thecase of a cloth or the like. The transparent substrate may be permittedto remain as it is on the article to provide a protective layer or,alternatively, it may be peeled off to make the image-receiving layerthe protective layer.

However, with a sheet having only a transparent receiving layer providedon a transparent substrate, there is the problem of difficulty ofdetecting the state of sheet delivery in the heat transfer device.Further, in transparency of the prior art, a support comprising apolyethyleneterephthalate film, or the like containing generallytitanium white, etc. has been used as laminated, freely peelable on theback surface of the substrate for the purpose of reinforcement of thesheet. Thus, in the image-receiving sheet for transfer onto atransferable article having a support in laminated state on thesubstrate back surface, the transparent substrate is generally as thinas about 6 to 25μ, but since the image-receiving sheet is furtherlaminated on the back surface with a support comprising a non-foamableresin, the rigidity as a whole becomes too high.

For this reason, the actual contact dot area between the heat transfersheet and the image-receiving sheet becomes smaller as compared with thedot area heated by a thermal head. As the result, the density of thetransferred image is low, and yet delivery of the image-receiving sheetduring heat transfer in the transfer device cannot be conducted smoothlyby means of the transfer device, whereby there has been the problem ofprinting drift or color drift in the case of performing overlayedtransfer repeatedly as in color transfer.

SUMMARY OF THE INVENTION

The present invention has been accomplished in view of the above pointsand is intended to provide an image-receiving sheet which has highprinting density and yet is free from printing drift, color drift, andother drawbacks.

Another object of the present invention is to provide an image-receivingsheet which can perform sheet delivery in a transfer device smoothly andyet without the possibility of incurring deleterious influence orcurling by the heat applied during transfer.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings:

FIGS. 1 through 5 are sectional views respectively showing specificexamples of the image-receiving sheet of the present invention, FIG. 3being a sectional view showing the state of transferring an image by theuse of the image-receiving sheet of the present invention to a specificarticle; and

FIG. 6 is a sectional view showing the state of the image transferred toa specific article.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings, preferred embodiments of the presentinvention will now be described.

As shown in the sectional view in FIG. 1, the first embodiment of theimage-receiving sheet of the present invention has a receiving layer 2on the surface of a base sheet 1 having a porous structure or a foamstructure.

In the example shown in FIG. 2, the base sheet 1 comprises a substrate1a and a support 1b. Further, in this example, an intermediate layer 3is formed between the base sheet 1 and the receiving layer 2.

The constitution and the materials of the image-receiving sheet of thepresent invention will first be described in detail primarily withrespect to these examples.

Base Sheet

In the present invention, the base sheet comprises one or two or morelayers, and at least one layer of the base sheet has a porous structureor a foam structure. The material having a porous or foam structure canbe obtained according to, for example, such methods as described below.

(a) The method in which a thermoplastic resin is stretched with additionof inorganic or organic fine particles, whereby voids are generatedaround the fine particles.

(b) The method in which an organic solvent solution of a synthetic resinis extruded through an orifice, and then introduced into a coagulatingbath to cause coagulation by desolventization, whereby voids aregenerated through elimination of the solvent.

(c) The method in which a resin is extruded together with a foamingagent to carry out extrusion foaming.

As the base sheet, laminated products of these materials can be alsoused. When produced according to the method of (c), those with smallcell sizes are particularly preferred.

As the material for the base sheet, one having high heat resistance suchas a polyester (e.g., polyethyleneterephthalate), an aliphatic polyamide(e.g., 6-nylon), an aromatic polyamide, polycarbonate, polyallylate,polyether, polyethersulfone, polyether ether ketone, polyether imide andpolyimide are preferred, but it is also possible to use polyolefins suchas polyethylene and polypropylene, polyvinyl chloride, polyvinylidenechloride, polyvinyl alcohol, acrylic resins, cellulose resins, styreneresins, ethylene-vinyl acetate copolymer, ethylene-vinyl alcoholcopolymer, ionomer, etc.

The thickness of the base sheet is preferably of the order of 50 to 200μm. As to the density of the base sheet 1 (density of the weight per 1m² divided by the thickness), it is preferably 90% or less, particularly80% or less, and 50% or more, relative to the density of the non-foamedproduct of the same material, for improvement of printing quality andmaximum heat insulating effect.

As shown in FIG. 2, in the present invention, the base sheet can be madeas a laminate of the substrate 1a and the support 1b, and in thisconstitution, by providing the support 1b, an excellent effect forimprovement of delivery performance of the sheet in the transfer devicefor sheet is exhibited. As the support 1b, a synthetic resin film, awhite synthetic resin film containing a pigment such as titanium white,etc., a cellulose fiber paper such as a coated paper or cast coatedpaper is used, and as the above synthetic resin, the same resins asthose for the substrate la can be employed, but other resins may also beemployed. When the support 1b is constituted of a synthetic resin filmor a white synthetic resin film, it may be constituted of either thesame material resin as the substrate 1 or a different material resin.

If the support 1b is laminated in a freely peelable state with thesubstrate 1a, the delivery performance of the sheet in the transferdevice during transfer can be improved, and also a procedure such aspeeling after transfer is possible. For laminating the support 1b as ina freely peelable manner with the substrate 1a, it is possible to employthe method in which both are caused to adhere with a weak tackifier orthe method in which the support 1b surface is subjected to a releasetreatment, and the substrate 1a is coated on the receiving layernon-forming surface with a strong tackifier, a heatsensitive adhesive,etc. and dried before being caused to adhere. In the latter method, thesubstrate 1a from which the support is peeled off (the receiving layerhaving already an image transferred thereon) can also be used as thelabel attached with the tackifier. Also, the support 1b can have adetection mark for positioning in the transfer device during heattransfer printing. Further, on the back of the support 1b, forimprovement of paper passage, a lubricating layer comprising an acrylicresin, methacrylic resin, etc. or an antistatic layer such as asurfactant can be formed.

The support 1b, when used for a use such as transferring the transferredimage further to another image-receiving member 15, will be finallypeeled off from the substrate 1a.

FIG. 3 indicates the manner in which transfer is carried out onto animage-receiving member 15 such as a card, reference numeral 14designating an image, 4 a primer, and 5 a weak tackifier layer.

Image-receiving sheets to be used by transfer onto articles such ascards and fabrics are generally of the following two types.

(I) A plastic film such as polyethyleneterephthalate is subjected to aprimer treatment, if necessary, and an image-receiving layer is providedthereon. The silicone which is the release agent on the image-receivingsurface is cured. On the other hand, on one surface of the foamedpolyethyleneterephthalate which is the support, a slip layer for makingdelivery within the printer smooth is provided and provided with markprinting, if necessary, while on the opposite surface is applied aprimer treatment, if necessary, followed by coating of a weak tackifierthereon. The transparent substrate provided with the above imagereceiving layer, at its surface having no image-receiving layer, iscaused by pressure to adhere with a weak tackifier thereby to provide animage-receiving sheet. A sublimatable dye image (ordinarily reverseimage) is formed at the image-receiving surface of the image-receivingsheet, and the image-receiving surface is caused by hot pressurizationwith hot rollers to adhere onto an article made readily adherable byprimer treatment, for example, the primer treated surface of a cardsubstrate. The support can be peeled off together with the weaktackifier to obtain a decorated article. In this case, the film such astransparent polyethyleneterephthalate becomes the protective layer toimprove the storability of the card. Particularly, when storability isimportant, it is desirable to add a photostabilizer, etc., internally ofthe transparent film and/or the image receiving layer.

(II) Alternatively, for making the support readily peelable, in place ofusing the weak tackifier as described above, an image-receiving sheetwith the following constitution can be also made. That is, on a smoothfilm of polyethyleneterephthalate, a peeling layer is formed and animage-receiving layer is provided thereon. In this case, the sheetassembly is so designed that the adhesive force between the peelinglayer and the smooth film will be weaker than the adhesive force betweenthe peeling layer and the image-receiving layer. On the other hand, thesurface of the foamed polyethyleneterephthalate which is the support, onwhich no slip layer is provided, is subjected to a primer treatment, ifnecessary, coated with an adhesive, and caused to adhere by contactingthe surface having no image-receiving layer of the smooth film providedwith the above image-receiving layer with the adhesive. After formationof a sublimating dye image on the image-receiving surface, heat transferis effected on an article similarly as described above to make adecorative article. In this case, the image-receiving layer or thepeeling layer functions as protection of the image.

In either of the cases (I) and (II), the transparent plastic sheet orthe smooth plastic film is preferably on the thinner side so that thecushioning characteristic of the foamed polyethyleneterephthalate whichis the support will contribute to the effect, and a film with athickness of about 6 to 25 μm is generally used.

The image-receiving sheet of the present invention, by the use of a basesheet comprising a material having a porous or foamed structure, canproduce a transferred image with high density by the cushioning actionand heat insulating action of the base sheet, and can also obtain smoothdelivery of the image-receiving sheet in the transfer device, wherebythere is no possibility of printing slippage due to irregularity ofdelivery or color drift during color transfer. Yet there is also nopossibility of curling of the substrate by heating during printing, thusproducing the excellent effect of obtaining a clear and good transferredimage.

Receiving Layer

For the receiving layer, it is desirable to use a resin havingdyeability with respect to a sublimatable dye and weathering resistance.Specifically, the following examples may be included.

(1) Saturated polyester resin, polyurethane resin, polystyrene resin,polyamide resin, vinyl chloride resin, vinyl chloride-vinyl acetatecopolymer resin, copolymer of vinyl chloride and acylic acid typemonomer, polyvinyl acetate, polycarbonate resin, epoxy resin, andethylenevinyl acetate type resin. Among these, copolymers of vinylchloride-acrylic acid type monomer and polyamide resin are particularlypreferred. Also, a resin composition composed mainly of vinyl chloridecan be formed into a film according to the film forming processingmethod such as the calendering method and used as the receiving layer,which can be used particularly with a foamed sheet caused to adherethereon or adhere in a freely peelable state and is particularlysuitable for OHP, labels, etc.

(2) When a copolymer of vinyl chloride with an acrylic acid type monomeris used as the resin for the receiving layer, a receiving layer havinggood dyeability as well as weathering resistance can be obtained.

Examples of acrylic acid type monomers are acrylates such as methylacrylate, ethyl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethylacrylate, and trimethylolpropane triacrylate; methacrylates such asmethyl methacrylate, t-butyl methacrylate, triethyleneglycoldimethacrylate, and trimethylolpropane methacrylate; acrylic acid ormethacrylic acid and acrylic acid metal salts.

As acrylates, those having a functional group, particularly acrylates ormethacrylates having a hydroxyl group in the side chain are desirablyused because dyeability can be remarkably enhanced.

The copolymerization ratio of vinyl chloride to an acrylic acid typemonomer is desirably vinyl chloride/acrylic acid type monomer=50 to90%/50 to 10%, and its molecular weight is 5,000 to 40,000, preferably10,000 to 30,000.

Also, it is possible to use a copolymer of vinyl chloride and an acrylicacid type monomer copolymerized with other monomers such asacrylonitrile, vinyl pyrrolidone, N-substituted maleimide, maleic acid,etc. In this case, the copolymerization ratio of other monomers isdesirably of the order of 0.1 to 30%.

(3) As the receiving layer resin, a resin having an amide bond(NH--CO--) or a modified resin which is a derivative of said resin maybe also used.

The resin having an amide bond is obtained by, for example,polycondensation of a dicarboxylic acid compound and a diamine compound.Examples of these dicarboxylic acids and diamines are as follows.

(A) Dicarboxylic Acids

1 aliphatic dicarboxylic acids such as oxalic acid, malonic acid,succinic acid, oleic acid, maleic acid, adipic acid, eraidic acid,azelaic acid, sebacic acid, eicosanic diacid, and linoleic acid, andderivatives thereof;

2 alicyclic dicarboxylic acid such as cyclopropane dicarboxylic acid,cyclohexane carboxylic acid, and bicyclooctane dicarboxylic acid, andderivatives thereof;

3 aromatic dicarboxylic acids such as phthalic acid, naphthalenedicarboxylic acid, biphenyl dicarboxylic acid, and isopropylidenedibenzoic acid, and derivatives thereof;

4 dicarboxylic acids such as oxaadipic acid, methyl9-oxabicyclo[3,3,1]nonane-2,6-dicarboxylate, and 4,5-imidazolecarboxylic acid, and derivatives thereof, and also dimers (dimericacids) of linoleic acid, oleic acid, eraidic acid, and tall oil fattyacid.

(B) Diaminegg Compounds

1 diamines such as ethylenediamine, trimethylenediamine,tetramethylenediamine, diaminobutane, pentamethylenediamine,hexamethylenediamine, heptamethylenediamine, octamethylenediamine,decamethylenediamine, and dodecamethylenediamine, and derivativesthereof;

2 diamines such as phenylenediamine, diaminotoluene, diaminophenol, andisophoronediamine, and derivatives thereof.

A receiving layer prepared by the use of these polyamide resins isparticularly excellent in dyeability.

(4) The receiving layer may be formed by the use of a resin compositioncomposed mainly of polyvinyl chloride. Such a resin is a resincomposition containing 50% by weight or more of polyvinyl chloride,specific examples of which are homopolymers only of polyvinyl chloride;copolymers of vinyl chloride copolymerized with 5 to 30% of vinylidenechloride, or an acrylate; a blend resin of polyvinyl chloride blendedwith other resins such as ethylene-vinyl acetate.

The resin composition composed mainly of polyvinyl chloride canincorporate 5 to 60%, preferably 10 to 50%, by weight of a plasticizer.If the amount of theplasticizer added is less than 5% by weight, theimage-receiving layer becomes rigid and dyeability of a dye duringtransfer will be lowered. On the contrary, if it exceeds 60% by weight,although dyeability can be improved, blurring of image is liable tooccur with elapse of time, whereby storability of image for a longperiod is inferior. Examples of the plasticizer are phthalic acidesters, dibasic acid esters, polyhydric alcohol esters, fatty acidesters, epoxy. fatty acid esters having the function as the stabilizer,and polymeric plasticizers such as ethylene-vinyl acetate copolymer,used singly or as combinations of two or more kinds.

(5) The above receiving layer resin which can be mixed with each othercan be used as a mixture. Also, another resin with good dye dyeabilitymay also be used as a mixture with the above receiving layer resin.

Examples of the resin with good dye dyeability are resins of polyestertype, polyurethane type, vinyl acetate type, polystyrene type, epoxytype, amino type, and ethylene-vinyl acetate type.

Formation of the receiving layer may be practiced with the use of acomposition for formation of a receiving layer obtained by dissolving ordispersing the receiving layer resin in a solvent according to a knowncoating method or printing method. Otherwise, after a layer has beenformed once on a temporary carrier separated from the foamed sheetsubstrate, it may then be transferred onto the foamed sheet substrate.

In the case of a resin composition composed mainly of polyvinylchloride, a film formed by the film forming processing method such asthe calendering method may be used as the receiving layer, and a foamedsheet may be caused to adhere on the opposite surface or to adhere in afreely peelable state to provide an image-receiving sheet.

In the composition for formation of receiving layer, for improvement ofthe weathering resistance of the transferred image, one or two or morekinds of UV-ray absorbers, photostabilizers or antioxidants, etc. may beadded, if necessary. These additives should be added each in an amountof 0.05 to 10 parts by weight based on 100 parts by weight of the resin.

It is also possible to add a white pigment in the composition forformation of the receiving layer for the purpose of improving whiteness,shielding property of the receiving layer, or further impartingwritability to the image-receiving sheet surface, etc. As the whitepigment, titanium oxide, zinc oxide, kaolin clay, calcium carbonate,silica, etc. can be employed, and the amount of the white pigment ispreferably 5 to 50 parts by weight based on 100 parts of the resinconstituting the receiving layer.

When the receiving layer is white and its surface reflectioncharacteristic is within a certain range, the degree of whiteness ishigh and the image transferred appears beautiful. Its desirable range.is such that the values of L, a and b as measured by the method definedby JIS-Z8722 and represented by the method defined by JIS-Z8730 are,respectively, L=90 or more, a=-1.0 to +2.0 and b=-2.0 to -5.0.

For falling within such a desirable range, it is necessary toincorporate a blue dye and a red dye other than the white pigment suchas titanium oxide, and to incorporate further, if necessary, afluorescent brightener, and control the respective contents. The aboveresin used in the receiving layer has a slightly yellow tint. Bycontrolling the contents of these additives, good whiteness can beobtained. The amount of the white pigment added in the receiving layeris desirably 30% or less, particularly 10% or less based on thereceiving layer resin. Accordingly, as the substrate coated with thereceiving layer, one having values of L, a and b approximately in theabove ranges is preferable, and particularly a foamed product ofpolyethyleneterephthalate is desirable.

The weight of the solvent in the receiving layer is desirably 1% or lessof the weight of the solvent soluble components for forming thereceiving layer. If the amount of the solvent remaining in the receivinglayer is 1% or more, the solvent odor remains, and also the image tendsto become obscure when stored for a long time after printing.

The thermoplastic resin for forming the receiving layer desirably has aglass transition point of 40° C. or higher. When the glass transitionpoint is lower than 40° C., dyeability can be improved, but the dyereceived tends to migrate toward the overlapped sheet side to beretransferred, and also the dye received is subjected to migration,whereby the image becomes obscure.

Release Agent, Release Agent Layer

The image-receiving sheet of the present invention can contain a releaseagent in the receiving layer for enhancing releasability from theheat-transfer sheet. Examples of such a release agent are solid waxessuch as polyethylene wax, amide wax, and Teflon powder, fluorine type,phosphoric acid ester type surfactants, and silicone oils, of whichsilicone oils are preferred.

As the above silicone oil, an oily one can be used, but a cured type oilis preferred. As the cured type silicone oil, the reaction cured type,the photocured type, the catalyst cured type, etc. may be used, but asilicone oil of the reaction cured type silicone oil is preferred. Asthe reaction cured type silicone oil, one obtained by the reactioncuring of an amino-modified silicone oil and an epoxy-modified siliconeoil is preferred. The amount of this cured type silicone oil ispreferably 0.5 to 30 parts by weight based on 100 parts by weight of theresin constituting the receiving layer.

Also, a release agent layer can be provided by coating a part or all ofthe surface of the receiving layer with the above release agentdissolved or dispersed in an appropriate solvent and then drying thecoating. As the release agent constituting the release agent layer, thereaction cured product of the amino-modified silicone oil and theepoxy-modified silicone oil as mentioned above is particularlypreferred. The release agent layer should have a thickness of 0.01 to 5pm, particularly 0.05 to 2 pm. The release agent layer may be providedon either a part of the surface of the receiving layer or the wholesurface. When it is provided on a part of the receiving layer surface,dot impact recording, heat-sensitive melting transfer recording orrecording with a pencil, etc. can be performed on the portion where norelease agent layer is provided. It is also possible to perform thesublimating transfer recording operation by another recording mode, suchas by performing sublimating transfer recording at the portion where therelease agent layer is provided and recording according to anotherrecording mode at the portion where no release agent is provided.

Further, in the present invention, in place of a silicone resin,fluorine resin, etc., or under a state of mixture with respectiveresins, a thin layer of the hot release agent as shown below may be alsoprovided:

(a) a hot release agent comprising as the main component a polymerhaving an organopolysiloxane component in the main chain or the sidechain of the polymer;

(b) a hot release agent comprising as the main component a polymerhaving a long-chain alkyl component in the side chain of the polymer.

Intermediate Layer

The intermediate layer 3 can be constituted of a resin such as apolyester, vinyl chloride-vinyl acetate copolymer, an acrylic resin, orpolyvinyl acetate. By the provision of the intermediate layer, printingdensity can be further enhanced through its cushioning property.

The intermediate layer 3 is provided by coating a solution of the aboveresin dissolved in a solvent and drying the coating, or by melting andextrusion coating of the above resin.

Surface Roughening Treatment

In the present invention, the receiving layer on either its outer orfront surface or the surface on the opposite side to the receiving layerforming surface can be suitably coated with an antistatic agent toprevent so-called "two-sheet feeding" during automatic paper feedingarising from electrostatic charges. However, when the effect ofpreventing two-sheet feeding only with the antistatic agent isinsufficient, this problem can be solved by toughening at least a partof the surface of the image receiving sheet and/or the surface on theback side.

Particularly, when the substrate of the image-receiving sheet comprisesa plastic sheet, a synthetic paper sheet or a laminate thereof with acellulose fiber paper, and automatic sheet feeding is performed with theimage-receiving sheets piled in a tray in the heat-sensitive printer,the image-receiving sheets tend to be delivered with two or more sheetsin superposed state (so-called two-sheet feeding) to cause inconvenientsheet clogging even if an antistatic treatment has been applied on thesurface of the sheets.

For solving this problem, it is desirable to roughen at least a part ofboth front and back surfaces of the image receiving sheet, for example,the non-image portion of the receiving surface or the back surface ofthe image-receiving sheet, by imparting fine unevenness thereto.

Label

The image-receiving sheet 31 of the present invention may be one havinga laminated structure, as shown in FIG. 4, comprising a releasetreatment layer 33, a tacky layer 34, a substrate 35 and a receivinglayer 36 successively laminated on a support 32. In this figure,reference numeral 37 designates cutting lines made by a half-cutprocess.

Also, the above image-receiving sheet 31 has a structure which ispeelable between a support portion 38, comprising the above support 32and the release treatment layer 33, and an image-receiving sheet portion39, comprising the tacky layer 34, the substrate 35 and the receivinglayer 36.

The above image-receiving portion 39 is the portion to be released fromthe support portion 38 and stuck onto various articles and comprises astructure in which the receiving layer 36 is provided on the substrate35, and the tacky layer 34 which enables adhering onto the surface of adesired article is secured to the back surface of the substrate 35.

The image-receiving sheet 31 is subjected to a half-cut process forproviding cutting lines 37 extending through all of the layersconstituting said support portion 38 or sheet portion 39, at specificpositions of the support portion 38 or the image-receiving sheet portion39 of the layer constitution comprising the laminated structure as shownin FIG. 4. The half-cut process is generally applied after thelamination working of the image-receiving sheet prior to transfer imagerecording by the use of a commercially available punching device, etc.by controlling the depth of the progress, but the half-cut process mayalso be applied after transfer image recording, and the number ofcutting lines, kinds of lines, shapes drawn by the lined, etc. aresuitably set.

When the half-cut process is applied at the support portion 38, aftertransfer image recording, the peeling operation for peeling the supportportion 38 from the image-receiving sheet portion 39 can be done easilyand rapidly. Also, in the case of this example, in sticking a layerpreferably with a thin thickness onto a card or the like, if the supportportion is removed by peeling all at once, only the image-receivingsheet with a thin thickness remaining becomes inconvenient in handling,whereby adequate sticking will be difficult. In such a case, by applyingthe half-cut process so as to peel off only the support portioncorresponding to the image forming portion to be stuck (e.g. image isformed at the central portion of the sheet) and permit the supportportion which becomes the remaining peripheral portion to remain,peeling can be done during sticking with only the support portioncorresponding to said stuck portion, and the image-receiving portion canbe supported by the remaining support portion to be handled veryconveniently, whereby adequate sticking working can be done. In thiscase, after the image-receiving sheet portion has been stuck onto anarticle, the remaining support portion and the image-receiving sheetportion of said support portion are removed.

On the other hand, as shown in FIG. 5, when the image-receiving portion39 is subjected to the half-cut process, the image-receiving sheetportion 39 can be sectionalized and, recording of desired transferimages carried out within the regions of the sections. Then theimage-receiving sheet portion 39 within the section surrounded by thecutting line 37 can be released correctly and easily divided from thesupporting portion 38.

In practically using the image-receiving sheet 31 constituted asdescribed above, it is combined with the heat transfer sheet, andthrough migration of the dye in the colorant layer in the heat transfersheet by heating by a thermal head, etc. to the receiving layer 36 ofthe image-receiving sheet, a transferred image is formed on theimage-receiving sheet. Then the image-forming sheet portion 39 is peeledoff from the support portion 38 along the cutting line 37 by thehalf-cut process, which step is followed by sticking of theimage-receiving sheet portion having the transferred image 14 formedthereon onto an intended article 15, as shown in FIG. 6. The article 15may be any article, provided that the transferred image can be plasteredthereon.

The image-receiving sheet having the above composition is suitable for ause in which a large number of face pictures are formed, subjected tohalf-cut for respective sections of the respective face pictures, andpeeled off to be stuck onto name cards or various ID cards.

Detection Mark

For distinguishing whether the image-receiving sheet is the correctsheet to be used for the heat-sensitive transfer printer, and also,performing positional determination between the heat-transfer sheet andthe image-receiving sheet, it is desirable to form a physicallydetectable detection mark on a part of the image-receiving sheet,ordinarily on the back surface of the sheet.

As a method for preparing the image-receiving sheet having the detectionmark, each sheet obtained by cutting a sheet of the image-receivingsheet in a wound-up state is printed with a physically detectable markat a position corresponding to a corner and/or a side, and then saidsheet is cut to give an image-receiving sheet having a detection mark atthe corner and/or the side.

Writing Treatment Layer

The image-receiving sheet of the present invention can have a writingtreatment layer provided at a specific position on the receiving layer.The writing treatment layer refers to one on which writing with apencil, a ball-point pen, a fountain pen, etc. or otherwise sealing,etc. can be done. By the provision of this layer, difficulty in writing,sealing, etc., because the receiving layer is generally constituted of aresin film surface, can be overcome, whereby comments, notes, etc. canbe written freely on this layer. The writing treatment layer is formedby the use of a resin such as hydroxyethyl cellulose, polyvinyl acetate,or styrenemaleic acid copolymer which is mixed with calcium carbonate,silica, clay, etc.

Storability Enhancing Treatment of Image

In the present invention, for storability enhancement of the transferredimage, a protective layer can be formed on the surface of the receivinglayer.

As the material for such protective layer, there are plastic films suchas those of polyethyleneterephthalate, polypropylene, and rigid vinylchloride, which are laminated on the receiving layer having an imageformed thereon through a heat-meltable sheet or an adhesive.

Instead of providing a protective layer, it is also possible to wrap thesheet with a plastic film such as one of rigid vinyl chloride,polypropylene or polyethyleneterephthalate, or to store the sheet in acase made of those films.

Also, in the present invention, after formation of a dye image on thereceiving layer of the image-receiving sheet, the dye forming the imagecan be amply color formed and dyed by heating with heating means such asa thermal head, heating rolls or a laminator, whereby an image havingexcellent image density, light resistance, stain resistance, etc. can beprovided.

Further, in the present invention, after formation of a dye image on thereceiving layer of the image-receiving sheet having a receiving layercomprising an uncured or semi-cured curable resin, the receiving layercan be cured by application of an energy such as heat or ionizableradiation ..to impart long term storability to the dye image.

Uses

The image-receiving sheet of the present invention is applicable forhard copy making of an image recorded on a CRT picture face or an imagerecorded by a magnetic recording means, and may be used as it is afterprinting, or otherwise used after printing, with peel-off of thesupport. Alternatively, after printing, it can be caused to adhere withthe printed surface pressed against an article on which it is to betransferred and then peeled off from the support before use.

Specific examples of uses are those as substitute products for printedmatter, particularly printed matter for correction, and otherwiseformation of face pictures of ID cards, formation of face pictures onname cards, picture attachments on telephone cards, premiums, postalcards, advertisements for windows, electric decorative signboards,various decorative articles, tags, labels for explanation ofmerchandise, labels for stationary articles, indices for audio cassettesor video cassettes, and other various uses.

Other Considerations

Ordinarily, image-receiving sheets are stored and handled in a state inwhich a large number of sheets are stacked. In this case, it ispreferable that the image-receiving sheets stacked in a large number bepackaged and sealed with a cover comprising a soft packaging materialand yet have a structure such that one end of said cover can be readilybroken to be removed. By making such a structure, in using practicallythis stack, the user can break one end of said package and set theimage-receiving sheets on a sheet-feeding cassette with the remainder ofthe cover still intact, that is without touching the image-receivingsheets internally of the cover by hand, whereby infiltration of dust orgrime can be prevented so far as possible.

Also, in using the image-receiving sheet of the present invention, it ispossible to use a sheet-feeding cassette provided with a cassette casewith a sealed structure which is detachable relative to the printer andhouses internally image-receiving sheets, the image-receiving sheettake-out outlet having been made openable.

The user, in using the paper-feeding cassette, merely opens the take-outoutlet and can set the cassette case on the printer as it is withouttouching the image-receiving sheets therein by hand, wherebyinfiltration of dust or grime into the sheet-feeding cassette or leavingof fingerprints on the image-receiving sheets can be prevented.

Also, in using the image-receiving sheets of the present invention, itis preferable to provide a box-shaped case for housing a large number ofstacked image-receiving sheets, which case is provided on one end with atake-out outlet for image-receiving sheets, a dust removing meansprovided at said take-out outlet, and a dust removing means for removingdust from the recording sheet during take-out of the image-receivingsheet, such as a dust removing brush or a dust removing tape.

Further, the heat-sensitive transfer printer may also be provided with ameans for removing dust on the image-receiving sheet. As the means forremoving dust, tacky rolls and/or deelectrification rolls can be used.

In formation of images by means of the sublimation transfer method, theimage reproductivity varies according to the quality of a heat transfersheet or an image receiving sheet and the fluctuation of a printeritself. Therefore, in using the present invention, it is preferable toprepare a reference color in advance in order to know the variation ofthe reproductivity of images.

Such a reference color may be prepared separately with the imagereceiving sheet, or the reference color may be formed on the part of theimage receiving sheet, preferably on the edge of the surface where areceiving layer is formed. The reference color comprises a thin and longcolor scale consisting divided small parts of color, e.g., yellow, cyan,magenta and black. This color scale has preferably the range from shadowto highlight in each color. In printing, another color scale (referencecolor) may be formed together with images. In this case, the color scaleformed with images is compared with the previously formed color scalethereby to inspect the reproductivity of images formed by sublimationprinting. Thus, the quality of the image receiving sheet and the heattransfer sheet and the fluctuation of the operation conditions of aprinter can be judged by users.

According to the result of the above determination, users can change theheat transfer sheet or the image receiving sheet, or adjust theoperation conditions of the thermal printer, thereby to enhance theimage reproductivity.

The present invention is described in more detail below by way ofspecific Examples, in which quantities expressed in parts and % are byweight unless otherwise specifically noted.

EXAMPLE A-1

A porous polyethyleneterephthalate film having a density of about 73%relative to the density of the non-foamed polyethyleneterephthalate film(thickness 100μ, density 1.04, produced by Dialoil K.K., commerciallyavailable as [foamed white polyester film]) was used as the substrate,and after an urethane type primer was applied and dried on one surfaceof this substrate, a composition for formation of a receiving layer ofthe following composition was applied by a Myer bar and dried (coatingamount after drying 6 g/m²) to form a receiving layer, thus obtaining animage-receiving sheet.

    ______________________________________                                        Compostition for forming receiving layer                                      ______________________________________                                        Polyester resin          70     parts                                         (Vylon 200, produced by Toyobo, Japan)                                        Polyester resin          30     parts                                         (Vylon 290, produced by Toyobo, Japan)                                        Amino-modified silicone  5      parts                                         (KF-393: produced by Shinetsu                                                 Kagaku Kogyo, Japan)                                                          Epoxy-modified silicone  5      parts                                         (X-22-343: produced by Shinetsu                                               Kagaku Kogyo, Japan)                                                          Methyl ethyl ketone      350    parts                                         Toluene                  350    parts                                         ______________________________________                                    

On the other hand, with the use of a polyester film with a thickness of4.5μ (Lumilar: .produced by Toray, Japan) having a heat-resistantlubricating layer comprising a thermosetting acrylic resin provided onone surface as the substrate, the ink compositions for formation of heattransfer layer with the following compositions were applied on thesubstrate on the surface on the side where the heat-resistantlubricating layer was provided and the opposite side each to a coatedamount after drying of 1 g/m² to obtain a heat transfer sheet.

    ______________________________________                                        Cyan ink composition for formation of heat transfer layer                     Disperse dye (Kayaset Blue 714,                                                                        5      parts                                         produced by Nippon Kayaku, Japan)                                             Polyvinyl butyral resin (Ethlec BX-1,                                                                  4      parts                                         produced by Sekisui Kagaku, Japan)                                            Methyl ethyl ketone      46     parts                                         Toluene                  45     parts                                         Magenta ink composition for formation of heat transfer layer                  Disperse dye             2.6    parts                                         (MS Red G:                                                                    produced by Mitsui Toatsu Kagaku, Japan)                                      (Disperse Red 60)                                                             Disperse dye             1.4    parts                                         (Macrolex Violet R: produced by Bayer)                                        (Disperse Violet 26)                                                          Polyvinyl butyral resin  4.3    parts                                         (Ethlec BX-1:                                                                 produced by Sekisui Kagaku, Japan)                                            Methyl ethyl ketone      45     parts                                         Toluene                  45     parts                                         Yellow ink composition for formation of heat transfer layer                   Disperse dye             5.5    parts                                         (Macrolex Yellow 6G: produced by Bayer)                                       (Disperse Yellow 201)                                                         Polyvinyl butyral resin  4.5    parts                                         (Ethlec BX-1,                                                                 produced by Sekisui Kagaku, Japan)                                            Methyl ethyl ketone      45     parts                                         Toluene                  45     parts                                         ______________________________________                                    

By the use of the heat transfer sheet together with the aboveimage-receiving sheet, printing was performed by means of a color videoprinter: VY-50 (produced by Hitachi Seisakusho) under the conditionsshown below, and the reflective density of cyan was measured by aMacbeth color densitometer RD-918 to be 1.95. Also, the printing densitywas found to be uniform over the entire printed surface, and goodtransfer image could be obtained, without drop-out of dot beingobserved, with high printing densities for all of the three colors,without coarseness, color drift of the three colors or groundirregularity. Further, by controlling the electrical energy applied onthe head by varying the pulse width, any desired printing density couldbe obtained with good reproducibility.

    ______________________________________                                        Printing conditions                                                           ______________________________________                                        Printing speed:       33.3   ms/line                                          Delivery pitch:       0.166  mm                                               Pulse width:          12.0   ms                                               Head application voltage:                                                                           11.0   V                                                ______________________________________                                    

COMPARATIVE EXAMPLE A-1

When printing was performed on an image-receiving sheet obtained as inExample A-1 except for changing the substrate to a non-foamed whitepolyethyleneterephthalate film (thickness 100μ, density 1.42, producedby Toray: E-20), the printing density was found to be lower as comparedwith Example A-1. There was coarseness in the half-tone image, and alsocolor drift of the three colors was observed.

EXAMPLE A-2

A porous polyethyleneterephthalate film having a density of about 80%relative to the density of the non-foamed film (thickness 75μ, density1.16, produced by Teijin K.K., commercially available as [porous PET])was used as the substrate, and a composition for formation of anintermediate layer shown below was applied and dried on one surface ofthis substrate (coating amount after drying 5 g/m²).

    ______________________________________                                        Composition for formation of intermediate layer                               ______________________________________                                        Polyester resin         60     parts                                          (Vylon 200, produced by Toyobo)                                               Polyester resin         40     parts                                          (Vylon 600, produced by Toyobo)                                               Solvent (methyl ethyl ketone/                                                                         650    parts                                          toluene = 1/1)                                                                ______________________________________                                    

Subsequently, on the intermediate layer formed as described above, acomposition for formation of a receiving layer with the followingcomposition was applied by a Myer bar and dried (coating amount afterdrying 5 g/m²) to form a receiving layer.

    ______________________________________                                        Composition for forming receiving layer                                       ______________________________________                                        Polyester resin           70     parts                                        (Vylon 200, produced by Toyobo)                                               Vinyl chloride-vinyl acetate compolymer                                                                 30     parts                                        (Vinylite VYHH, produced by                                                   Union Carbide)                                                                Amino-modified silicone   7      parts                                        (KF-393: produced by Shinetsu                                                 Kagaku Kogyo, Japan)                                                          Epoxy-modified silicone   7      parts                                        (X-22-343: produced by Shinetsu                                               Kahaku Kogyo, Japan)                                                          Solvent (methyl ethyl ketone/toluene = 1/1)                                                             700    parts                                        ______________________________________                                    

Further, on the surface on which a receiving layer was not formed of thesubstrate having a receiving layer formed thereon, a tackifier (FinetackSPS-1001, produced by Dainippon Ink Kogyo K.K.) was applied and dried(coating amount after drying about 20 g/m²) and caused to adhere ontothe release treated surface of a commercially available releasable paperto provide an image-receiving sheet.

As the result of the same printing operation as in Example A-1 on theimage-receiving sheet, the image density was high without color drift ofthe three colors. This sheet was suitable as a decorative label when thereleasable paper was peeled off.

COMPARATIVE EXAMPLE A-2

An image-receiving sheet was obtained as in Example A-2 except forchanging the substrate to a non-foamed white polyethyleneterephthalatefilm (thickness 75μ, density 1.42, produced by Toray: E-20). Whenprinting was performed on the sheet in the same manner as in ExampleA-1, the image density was found to be lower as compared with that inExample A-1. There was coarseness in the half-tone image, and also colordrift of the three colors was detected.

EXAMPLE A-3

A foamed polypropylene film having a density of about 69% relative tothe density of non-foamed film (thickness 60μ, density 0.62, produced byToray: Torefan BOYP) was used as the substrate, and, after an urethanetype primer was applied and dried thereon, a receiving layer was furtherprovided in the same manner as in Example A-1 (coated amount afterdrying 5 g/m²) to provide an image-receiving sheet. When printing wasperformed on the image-receiving sheet in the same manner as in ExampleA-1, the printing density was high, and also no drop-out of dots wasobservable. Furthermore, a good image could be obtained without colordrift of the three colors.

EXAMPLE A-4

Image-receiving sheets were obtained as in Example A-1 except for theuse of the following composition (A) and a composition to which ananatase type titanium oxide (produced by Titanium Kogyo; KA-10), abenzooxazole type fluorescent brightener (produced by CIBAGEIGY Co.;Uvitex OB), a colorant dye (produced by Nippon Kayaku; Kayaset Blue-N),a red dye (produced by Bayer Co.; Macrolex Red Viotet R) had been addedin amounts shown in Table 1.

    ______________________________________                                        Compostion (A) for forming receiving layer                                    ______________________________________                                        Polyester resin          6.6    parts                                         (Vylon 600, produced by Toyobo, Japan)                                        Polyvinyl chloride acetate                                                                             9.0    parts                                         (produced by Denki Kagaku: #1000A)                                            Amino-modified silicone oil                                                                            0.3    part                                          (produced by Shinetsu kagaku, Japan;                                          X-22-3050C)                                                                   Epoxy-modified silicone oil                                                                            0.3    part                                          (produced by Shinetsu Kagaku, Japan;                                          X-22-3000E)                                                                   Toluene                  42.2   parts                                         Methyl ethyl ketone      42.2   parts                                         ______________________________________                                    

L, a and b values of the image-receiving sheets obtained as describedabove were measured by SM color computer (SM-4CH Model) produced by SugaTesting Machine. The measured values are shown in the following Table 1.

                                      TABLE 1                                     __________________________________________________________________________       White                                                                         pigment                                                                             Blue dye                                                                            Red dye          Visual                                        No.                                                                              (wt. parts)                                                                         (wt. parts)                                                                         (wt. parts)                                                                         L  a   b   judgement                                     __________________________________________________________________________    1  0     0     0     94.38                                                                            -0.95                                                                              2.02                                                                             tinted in yellow                              2  0     0.003 0.003 90.51                                                                            -0.29                                                                             -3.89                                                                             good white                                    3  0.75  0.003 0.003 92.50                                                                             0.12                                                                             -3.52                                                                             good white                                    __________________________________________________________________________

EXAMPLE A-5

Two kinds of image-receiving sheets were obtained as in Example A-1except for the use of the following comopsition (B) and the followingcomposition (C) as the composition for formation of receiving layer,respectively. Also, for comparison, an image-receiving sheet wasprepared by the use of the following composition (D).

    ______________________________________                                        Composition (B) for forming receiving layer                                   Vinyl chloride/2-hydroxyethyl acrylate =                                                               2      parts                                         80/20 (each mole) copolymer resin                                             Amino-modified silicone  0.125  part                                          (KF-393: produced by Shinetsu Silicone,                                       Japan)                                                                        Epoxy-modified silicone  0.125  part                                          (X-22-343: produced by Shinetsu Silicone,                                     Japan)                                                                        Toluene                  10     parts                                         Methyl ethyl ketone      10     parts                                         Composition (C) for forming receiving layer                                   Vinyl chloride/2-hydroxyethyl acrylate                                        maleic acid = 83.6/16/0.4 (each mole)                                         Copolymer resin          2      parts                                         (Ethlec E-C110, produced by Sekisui                                           Kagaku Kogyo, K.K., Japan)                                                    Amino-modified silicone  0.125  part                                          (KF-393: produced by Shinetsu Silicone,                                       Japan)                                                                        Epoxy-modified silicone  0.125  part                                          (X-22-343: produced by Shinetsu Silicone,                                     Japan)                                                                        Toluene                  10     parts                                         Methyl ethyl ketone      10     parts                                         Composition (D) for forming receiving layer                                   Polyester resin          2      parts                                         (Vylon 200, produced by Toyobo, Japan)                                        Elvaroy 741              2      parts                                         (EVA type polymeric plasticizer,                                              produced by Mitsui Polychemical, Japan)                                       Amino-modified silicone  0.125  part                                          (KF-393: produced by Shinetsu                                                 Silicone, Japan)                                                              Epoxy-modified silicone  0.125  part                                          (X-22-343: produced by Shinetsu                                               Silicone, Japan)                                                              Toluene                  10     parts                                         Methyl ethyl ketone      10     parts                                         ______________________________________                                    

After printing was performed on each image-receiving sheet obtainedaccording to the same method as in Example A-1, weathering resistancetest was conducted to obtain the results as shown below in Table 2.

Weathering Resistance Test

Weathering resistance was measured according to JIS L0842, and thosewith the initial fastness in the second exposure method of JIS L0841exceeding class 3 were rated as ⊚, and those not satisfying class 3 asx.

                  TABLE 2                                                         ______________________________________                                                Weathering resistance                                                         test results                                                          ______________________________________                                        B         ⊚                                                    C         ⊚                                                    D         x                                                                   ______________________________________                                    

EXAMPLE A-6

As the composition for forming a receiving layer, the followingcomposition (E) was used, and further the composition (F) forcomparative purpose, to obtain 3 kinds of image-receiving sheets.

    ______________________________________                                        Composition (E) for forming receiving layer                                   ______________________________________                                        Polyamide resin           10    parts                                         (produced by Henkel Hakusuisha:                                               Versamide 744)                                                                Amino-modified silicone oil                                                                             1     part                                          (produced by Shinetsu Kagaku Kogyo:                                           KF-393)                                                                       Epoxy-modified silicone oil                                                                             1     part                                          (produced by Shinetsu Kagaku Kogyo:                                           X-22-343)                                                                     Toluene                   20    parts                                         Isopropyl alcohol         20    parts                                         ______________________________________                                    

After printing was performed on the image-receiving sheet obtained inthe same manner as in Example A-1, the relative density was measured bya densitometer RD-918 produced by Macbeth Co., USA. As the result, itwas found to be 1.5 for one using the composition (E) and 1.0 for oneusing the composition (F).

EXAMPLE B-1

By use of a polyester film (thickness 12μ) as the substrate, a polyesterresin type primer was applied on one surface thereof and dried, whichstep was followed further by coating and drying of a composition forforming a receiving layer with the following composition to a weight of7 g/m² after drying.

    ______________________________________                                        Composition for forming receiving layer                                       ______________________________________                                        Polyester resin (produced by Toyobo,                                                                   100    parts                                         Vylon 200)                                                                    Amino-modified silicone (produced by                                                                   5      parts                                         Shinetsu Kagaku Kogyo, KF-393)                                                Epoxy-modified silicone (produced by                                                                   5      parts                                         Shinetsu Kagaku Kogyo, X-22-343)                                              Solvent (methyl ethyl ketone/toluene/                                                                  900    parts                                         cyclohexanone = 4/2/2)                                                        ______________________________________                                    

The above composition was coated, dried, left to stand for one day andthereafter heated at 100° C. for 30 minutes to permit the silicone tobleed on the surface and thereby to provide a receiving layer having arelease layer comprising hardened silicone on the surface.

Next , by the use of a porous polyethyleneterephthalate film having adensity of about 72% relative to the density of the non-foamedpolyethyleneterephthalate film (thickness 100μ, density 1.04, producedby Diafoil K.K.: commercially available as [foamed white polyesterfilm]) as the support, and after coating and drying of an urethane typeprimer thereon, a weak tackifier (acrylic emulsion, produced by SekisuiKagaku Kogyo K.K., Esdaine AE-206) was applied by means of a Myer barand dried to provide a weak tackifier with a dried weight of 4 g/m²thereon, which was then pressure laminated onto a substrate having theabove receiving layer formed thereon on the side without a receivinglayer formed thereon to provide an image-receiving sheet.

On the receiving layer of the image-receiving sheet, a sublimatingtransfer film having a sublimatable cyan dye (molecular weight of 250 ormore) carried with a binder resin was superposed, heat energy wasimparted with a thermal head connected to the electrical signals of thecyan component obtained by color resolution of a face photograph toobtain a cyan image. Subsequently, sublimation transfer was successivelyperformed with a sublimation transfer film by the use of a sublimatablemagenta dye (molecular weight of 250 or more) and a sublimation transferfilm by use of a sublimatable yellow dye (molecular weight of 250 ormore), thus forming a display image comprising the face photography offull color and otherwise letters and figures.

The color image formed by transfer as described above was found to befree of color drift of the three colors and also have ample imagedensity.

After the receiving layer side of the image-receiving sheet having theabove image transferred thereon was superposed on the primer-treatedsurface of a card substrate comprising a white transparent rigid vinylchloride resin sheet previously subjected to primer treatment with athickness of 10μ, the card substrate and the image-receiving sheet werepressure bonded by heating the image-receiving sheet from the supportside by means of hot rollers of 200° C., which step was followed bypeel-off of the support, thereby transferring the image transferred ontothe image-receiving sheet onto the card substrate.

The surface of the card was found to be smooth as a whole withoutformation of unevenness by the heat during transfer, and also there wasno rising at all at the image portion. Further, the image on the cardwas free of distortion of the image or interlayer peel-off even in theaccelerated test in which it was maintained in an atmosphere of 40° C.for 3 months. Also, when light resistance test was performed by a carbonblack lamp, the results were found to be JIS class 4 to 5, thusexhibiting good performance. As to scratching of the surface, etc., goodresistance was also exhibited.

COMPARATIVE EXAMPLE B-1

An image-receiving sheet was obtained as in Example B-1 except for theuse of a non-foamed white polyester film (thickness 100μ, density 1.45,produced by Toray: E-20) as the support. When a color image wastransferred onto the image-receiving sheet in the same manner as inExample B-1, color drift of the three colors was observed and also theimage density was low

EXAMPLE B-2

By the use of a cast coated paper (thickness 95μ) as the substrate, acomposition for forming an intermediate layer with the followingcomposition was applied and dried to a dry weight of 5 g/m² to form anintermediate layer.

    ______________________________________                                        Composition for forming intermediate layer                                    ______________________________________                                        Polyester resin (produced by Toyobo:                                                                    50     parts                                        Vylon 600)                                                                    Polyester resin (produced by Toyobo:                                                                    50     parts                                        Vylon 200)                                                                    Solvent (methyl ethyl ketone/toluene = 1/1)                                                             500    parts                                        ______________________________________                                    

On the intermediate layer was applied and dried the same composition forforming receiving layer as in Example B-1. Then heating was carried outat 100° C. for 30 minutes to form a receiving layer having a hardenedsilicone layer on the surface.

Next, a porous polyethyleneterephthalate film having a density of about84% relative to the non-foamed film (thickness 75μ, density 1.22,produced by Teijin K.K.: commercially available as [porous PET]) wasprovided with a weak tackifier layer thereon in the same manner as inExample B-2 to a dry weight of 3 g/m² and then pressure laminated ontothe surface without a receiving layer formed thereon of the substratehaving the above receiving layer formed thereon.

When transfer of a color image was carried out onto the image-receivingsheet in the same manner as in Example B-1, the transferred imageobtained was found to be free of color drift of the three colors, andalso to have ample color density.

EXAMPLE B-3

By the use of a polyethyleneterephthalate film (thickness 9μ) as thesubstrate, release treatment was applied by coating a solvent solutionof an acrylic resin (produced by Mitsubishi Rayon, Dianal BR 85) thereonin a quantity of 1 g/m² (on drying).

Next, on the surface which had been subjected to the release treatment,a composition for forming a receiving layer having the followingcomposition was applied and dried to a dry weight of 6 g/m² to form areceiving . layer.

    ______________________________________                                        Composition for forming receiving layer                                       ______________________________________                                        Polyester resin (produced by Toyobo:                                                                    70     parts                                        Vylon 600)                                                                    Vinyl chloride-vinyl acetate copolymer                                                                  30     parts                                        (produced by Union Carbide:-Vinylite VAGH)                                    Amino-modified silicone (produced by                                                                    5      parts                                        Shinetsu Kagaku Kogyo: KF-393)                                                Epoxy-modified silicone (produced by                                                                    5      parts                                        Shinetsu Kagaku Kogyo: X-22-343)                                              Solvent (methyl ethyl ketone/toluene = 1/1)                                                             700    parts                                        ______________________________________                                    

On the other hand, after the same porous polyethyleneterephthalate filmas used in Example B-1 was coated with a polyester type adhesive anddried, it was pressure laminated onto surface without a receiving layerof the substrate having the above receiving layer formed thereon toobtain an image-receiving sheet.

When color image transfer was performed in the same manner as in ExampleB-1, a transferred image without color drift of the three colors, andalso with ample image density was obtained. Subsequently, after thesheet was pressure bonded onto the same card substrate as in ExampleB-1, the support was peeled off. As the result, the surface of the cardwas found to be smooth as a whole without formation of unevenness by theheat during transfer, and there was no rising at all at the imageportion. Further, the image on the card was free of distortion of imageor interlayer peel-off even in the accelerated test when maintained inan atmosphere of 40° C. for 3 months. Also, when the light resistancetest of JIS with a carbon black lamp was conducted, the results were JISclass 4 to 5, thus indicating good performance. As to scratching of thesurface, etc., good resistance was also exhibited.

EXAMPLE C-1

A sheet substrate comprising a transparent polyethyleneterephthalatefilm with a thickness of 25 μm (produced by Toray: T type) was coated byMyer bar thereon with the following composition for formingimage-receiving layer to a dry weight of about 5 g/m² to form animage-receiving layer, followed by aging treatment in an oven 100° C.for 10 minutes.

    ______________________________________                                        Composition for forming image-receiving layer                                 ______________________________________                                        Polyester resin (produced by Toyobo:                                                                   12    parts                                          Vylon 600)                                                                    Vinyl chloride-vinyl acetate copolmer                                                                  8     parts                                          (produced by Denki Kagaku Kogyo:                                              1000A)                                                                        Amino-modified silicone (produced by                                                                   1     part                                           Shinetsu Kagaku Kogyo: KF 393)                                                Epoxy-modified silicone (produced by                                                                   1     part                                           Shinetsu Kagaku Kogyo: X-22-343)                                              Methyl ethyl ketone (= 1/1)                                                                            78    parts                                          ______________________________________                                    

On the other hand, after a release treatment layer of a dry weight of 1g/m² was formed by coating of a solvent solution of an acrylic resin(produced by Mitsubishi Rayon, Dianal BR85) on a foamedpolyethyleneterephthalate sheet with a thickness of 100 μm (produced byDiafoil K.K.: W-900E), a strong tackifier comprising the followingcomposition was coated on the surface thereof to a dry weight of about18 g/m².

    ______________________________________                                        Strong tackifier                                                              ______________________________________                                        Acrylic tackifier (produced by                                                                        40    parts                                           Toyo Ink: BPS4627-6S)                                                         Toluene                 60    parts                                           ______________________________________                                    

The above sheet substrate surface was laminated in opposed staterelative to the strong tackifier layer surface. Then, from the foamedsheet side, a half-cut process extending in a rectangular linear shapeof 60 mm ×90 mm to the release treatment layer was applied to obtain animage-receiving sheet.

By the use of this image-receiving sheet and by means of a color videoprinter (produced by Hitachi Seisakusho: VY-100), a human face wasprinted out with the video camera input on the image-receiving layersurface corresponding to the rectangular region corresponding to thatapplied with the half-cut process. In the transfer recording in thiscase, a clear image with extremely high image density could be obtained.

Next, the foamed sheet within the rectangular region which had beensubjected to the half-cut process was removed by peeling, and with awhite polyethyleneterephthalate sheet comprising a planar shape of 55mm×85 mm (thickness 250 μm) placed on the image-receiving sheet portionfrom which the foamed sheet was removed, the laminate was passed throughlaminate rolls. Next, sheet portions such as the unnecessary foamedsheet, image-receiving layer, etc. were removed by cutting to prepare anID card having an image-receiving sheet portion with the abovetransferred image recorded thereon.

The peel-off resistance strength of the image-receiving sheet portion inthis card had ample adhesive strength, i.e., 1.5 kg/l cm width, and alsobecause sticking of the image-receiving sheet onto the card wasperformed under in a state with the foamed sheet (support portion)remaining like a brim around the image forming portion, the sheet wasfirmly flexible with good handling adaptability, whereby sticking wasfacilitated.

EXAMPLE C-1

In the same manner as in Example C-1, an image receiving layer wasformed on the sheet substrate to prepare a part of the image receivingsheet.

On the other hand, a transparent polyethyleneterephthalate filmsubjected to peeling treatment (produced by Sanei Kagaku Kogyo, K.K.:RFT-25) was laminated on the same foamed sheet as in Example C-1 throughan adhesive comprising tile following composition (dry coated amount 3g/m²). T1 -Adhesive? -Adhesive (produced by Takeda Yakuhin 10 parts-Kogyo: Takelac A540) -Curing agent (produced by Takeda 1 part -YakuhinKogyo: A50)? -

Next, on the above film layer surface, the same strong tackifier as inExample C-1 was formed by coating, and after the film was laminated withthe tackifier layer opposed to a part of the sheet substrate of theabove image-receiving sheet, a half-cut process which cut theimage-receiving layer/polyethyleneterephthalate film/tackifier layer wasapplied to obtain an image-receiving sheet.

By the use of .the image-receiving sheet obtained, a transferred imagewas recorded similarly as in Example C-1, and an ID card was prepared bythe use thereof.

Also, on this card, a clear transferred image could be obtainedsimilarly as in Example C-1, and also the sticking work at theimage-receiving sheet portion was facilitated, and yet the adhesivestrength at the image-receiving sheet was also ample.

EXAMPLE D-1

By use of a foamed polyester sheet with a density of 0.7, a thickness of60 μm and a Bekk smoothness of about 1,2000 sec. and a natural paper(produced by Kanzaki Seishi: "Newtop" thickness about 60μ) as the corematerial, a sheet comprising a constitution of foamed polyester/naturalpaper/foamed polyester was prepared. At this time, an adhesive for drylamination (polyester polyol/isocyanate, coated amount about 3 g/m²) wasemployed.

After one surface of this sheet was coated with the composition forreceiving layer in Example A-1 to a dry coated amount of 4 g/m², curingwas effected at 100° C. for 30 minutes to provide an image-receivingsheet D-1 shown below.

On the other hand, for comparative purpose, image-receiving sheets withthe following structures were similarly prepared.

(a) image-receiving layer/foamed PET 60μ/paper 60μ

(b) image-receiving layer/synthetic paper 60μ/paper 60μ/synthetic paper60μ

D-1: image-receiving layer/foamed PET 60μ/paper 60μ/foamed PET 60μ

As the synthetic paper, FPG #60 produced by Oji-Yuka was employed.

The above four kinds of image-receiving sheets were cut into sizes of 10cm×10 cm, and curled amounts (environmental curling) were measured underthe respective conditions of:

(i): -20° C./60° C. each 8 hours×8 cycles; and

(ii): 40° C. 90% RH×100 hours

Also, printing was performed on the above respective image-receivingsheets cut, and the printed state, particularly the printed state at thelight portion (coarseness, namely transfer badness), was observed andcurling after printing (printing curling) was measured.

    ______________________________________                                                D-1       (a)         (b)                                             ______________________________________                                        Coarseness                                                                              Substantially                                                                             Substantially                                                                             Slightly do                                           none        none                                                    Printing curling                                                                        2-3 mm      4-5 mm      5-7 mm                                      Environmental                                                                           3-5 mm      Unmeasurably                                                                              3-5mm                                       curling               wound                                                   ______________________________________                                    

What is claimed is:
 1. A heat transfer sheet for use in thermal transferrecording, comprising:a substrate; and a dye layer formed on thesubstrate, said dye layer comprising a dye and a binder, said dyecomprising Disperse Yellow
 201. 2. The heat transfer sheet according toclaim 1, further comprising a heat-resistant lubricating layer formed ona surface of the substrate other than the surface on which said dyelayer is formed.